1. Field of the Invention
The present invention relates to a LED light for illumination and more particularly to a LED lighting device which can be assembled with more or less units based on the requirement of brightness of the illumination and part of the components can be replaced when the LED lighting device is out of order.
2. The Prior Arts
The light emitting diode (LED) is becoming more popular for applying in illuminating purpose because of its characteristics of smaller size, lower energy consumption and longer lifetime than conventional lighting devices, as well as the remarkable technique advance in the brightness of illumination. Because of the small size of LED, the lumen of a single LED is still lower than that of an incandescent bulb, a fluorescent lamp or conventional lamps. Therefore, the LED lighting device presently on the market is usually a LED module composed of a plurality of LEDs. The light is concentrated from the plurality of LEDs to provide sufficient brightness for illumination. For example, a plurality of LEDs are assembled on a circuit board having a specific area or assembled in a lamp case for concentrating the light of the LEDs to provide the same illumination as a conventional light bulb or better illumination than a conventional light bulb. Furthermore, only 15 to 20 percent of an input power of a high power LED is converted into light and the remained 80 to 85 percent of the input power is converted into heat. Therefore, the LED module has to be equipped with an efficient heat sink to dissipate the heat and prevent the interfaces of the LED from being overheated to affect the illumination efficiency of the LED and to reduce the lifetime of the LED.
A LED lighting device served as a regular street lamp or outdoor lighting device usually includes a heatsink, a power supply and a LED module. The LED module includes a plurality of LEDs disposed on a circuit board and the LEDs would radiate the light after the power is turned on and supplied to the circuit board. The heatsink comprises a base and a plurality of fins disposed on a side of the base. The LED module is disposed on another side of the base opposite to the side where the fins are disposed. Thereby, the heat generated by the illuminating LED module is transferred to the fins and the heat is carried away from the fins by air flow.
Depending on the required brightness of illumination of the conventional LED lighting device mentioned above, the area of the LED module and the quantity of the LED are determined. The heatsink having a specific area is determined corresponding to the LED module and the power supply having a specific power is determined corresponding to the LED module. After the LED module, the heatsink and the power supply are assembled, it is a finished product of the LED lighting device. When it needs to increase or reduce the brightness of the illumination, the LED module, the heatsink or the power supply can not be expanded or contracted alone to adjust the brightness of illumination required for the site. The LED module, the heatsink and the power supply have to be replaced all together and matched again correspondingly. Therefore, the conventional LED lighting device lacks the flexibility of assembling and is not economical.
Furthermore, when some of the LED chips or part of the other electronic components of the LED module is in failure and needs replacement, it can not replace the failure part only and has to replace the entire LED module. In other words, the other non-failure parts are also replaced as well as the failure parts at the same time, which is uneconomical.